Method for the separation of chemically modified rosins and their esters into components



Patented Feb. 20, 1940 UNrro SA'iES PATENT- OFFICE METHOD FOR THE SEPARATION OF CHEMI- CALLY MODIFIED ROSINS AND THEIR ESTERS INTO COMPONENTS Joseph N. Borglin, Wilmington, DeL, assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Application September 28, 1939, Serial No. 296,945

10 Claims. 01. 260 -103) This invention relates to a method for the separation of chemically modified resins and their esters into components, and more particularly the separation of chemically modified rosins and their esters into components by treatment with a selective solvent.

: Due to the complexity of the chemical structure of rosin, treatments for the production of chemical modifications practicallyv always result 10 in products which are mixtures of two or more chemical compounds. The product may contain unchanged rosin or the rosin may be converted into two or more different materials, or both. The esterification of such a modified product pro- 5 duces a modified rosin ester which, similarly, is

a mixture of chemically different esters. Likewise, esterification of rosin and then treatment to produce chemical modification, gives a' product which is a mixture of chemically dilferent esters. -20 Thus, for example, the hydrogenation of rosin may result in a mixture of unchanged rosin and dihydro-rosin. More complete hydrogenation results in a mixture of dihydro-rosin and tetrahydro-rosin. The production of a product which 25 :is entirely tetrahydro-rosin has so far proved impossible. The esterification of a hydrogenated rosin results in a mixture of rosin esters. Likewise, the hydrogenation. of rosin esters results in a mixture of ordinary rosin ester and dihydrorosin ester or a mixture of dihydro-rosin ester and tetrahydro-rosin ester.

The separation of the chemically difierent com.-

ponents of the chemically modified resins has heretofore been practically impossible, and the various commercial products have been complex mixtures of compounds of different chemical structure. No successful method for separating the components of such mixtures has been developed, in spite of the fact that it has been fully 40 realized that such separation wouldbe of great value from a commercial standpoint, as well as from a scientific standpoint.

Now I have found that I can separate chemicallymodified resins and chemically modified rosin esters into their components by a method which is relativeiy simple, efficient and adaptable to commercial operation. 1 accomplish this by treating a chemically modified rosin or a chemically vmodified rosin ester with a substance selected from the group of substances now known to the art to be selective solvents for the visibleand latent color bodies of rosin.

The process in accordance with this invention consists of treating a modified rosin or modified rosin ester with a solvent which is a selective 5 solvent for the color bodies of rosin, separating the selective solvent from the undissolved component of the rnodified rosin or rosin ester and recovering the component of. the modified rosin dissolved therein, as, for example, by evaporating the selective solvent. This process can be repeated as many times as necessary to produce the desired separation of the components.

In carrying out this method, the modified rosins or rosin esters may or may not be first dissolved in a solvent therefor which is immiscible with the selective solvent which is used. Ordinarily, it

' will be found convenient to use such a solvent,

particularly if the modified rosin or rosin ester treated is a solid at the temperature of treatment. When it is desired to use a solvent for the modified rosin or modified rosin ester, the procedure in accordance with this invention will consist of dissolving the modified rosin or modified rosin ester in the solvent, contacting the solution so formed with a selective rosin color body solvent immiscible therewith, separating the two solutions thus formed, and recovering a component of the modified rosin or modified rosin ester from each solution as, for example, by evaporatingthe respec- 3o to modify its chemical structure, sothat the resultant product is a mixture of two or more chemically difierent substances. The hydrogenation of rosin or a rosin ester in the presence of a suitable catalyst according to methods known to the art produces such a modified rosin or modified rosin ester. The esterification of a hydrogenated rosin, likewise, produces such an ester.

The polymerization of rosin or a rosin ester to increase its molecular weight and melting point by treatment with a polymerizing agent, for example, volatile metal halides, as, boron trifiuoride, zinc chloride, stannic chloride, aluminum chloride, ferric chloride; mineral acids, as, sulfuric acid, phosphoric acid; fullers earth; hydrogen fluoride; acid salts, as sodium acid sulfate, etc.; metallic silicon; hydro fiuoro-boric acid; etc., according to methods known to the art, produces such a modified rosin or modified rosin ester. Such a modified rosin ester may also be produced by esterifying a polymerized rosin.

Again, the treatment of rosin or a rosin ester with a suitable catalyst, as, for example, a hydrogenation catalyst, as nickel, nickel chromite, platinum, palladium, etc., at an elevated temperature of, for example, from about 150 C. to about 200 C. and without reaction between the rosin or rosin ester and any added substance, to produce an intraand inter-molecular rearrangement within the hydrocarbon nucleus of the rosin or rosin ester with a reduction in the apparent unsaturation as disclosed in the copending application of Edwin R. Littmann, Serial No. 84,877, filed June 12, 1936, produces a modified rosin or modified rosin ester which may be treated in accordance with this invention. Such modified rosins and modified rosin esters will hereinafter be termed Hyex rosins and I-Iyex rosin esters, respectively. The esterification of a I-Iyex rosin also produces such a chemically modified rosin ester.

The modified rosins which I treat in accordance with this invention may be any grade of wood or gum rosin which has been treated to modify its chemical structure so that the product is a mixture of two or more chemically different materials. The esters of the modified rosins which I treat may be produced by the esterification of modified rosins or may be produced by the chemical modification of ordinary esters of rosins, and may be esters of either a monohydric or a polyhydric alcohol. Thus, esters of rosins with monohydric alcohols, such as, for example, methanol, ethanol, propanol, butanol, amyl alcohol, cetyl alcohol, lauryl alcohol, stearyl alcohol, furfuryl alcohol, hydrofurfuryl alcohol, abietanol,hydroabietanol, phenol, benzyl alcohol, etc., or with polyhydric alcohols, such as, for example, ethylene glycol, diethylene glycol, triethylene glycol, glycerol, sorbitol, mannitol, erythritol, pentaerythritol, etc., may be treated by my new method.

The selective solvent which I use in accordance with this invention may be any of the various selective solvents for the visible and latent color bodies of rosins and rosin esters heretofore known. Thus, I may use iurfural, furfuryl alcohol, a chlorohydrin, as, ethylene chlorohydrin, propylene chlorohydrin, etc., aniline, phenol, resorcinol, ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, trimethylene glycol, glycerol, butyl glycerol, ethyl formate, methyl acetate, methyl formate, methyl orthonitrobenzoate, methyl furoate, alkyl formate, monoaoetin, diacetin, triacetin, ethylene glycol monoacetate, methanol, hydroxyl alkyl amine, as triethanolamine, a solution of oxalic acid in water or in methanol, ethanol or other lower aliphatic alcohol, ethylene glycol monoethyl ether, or other immiscible glycol ether, ethylene glycol monoacetate, or other immiscible glycol ester, methyl thiocyanate, ethyl thiocyanate, acetom'trile, acetic acid, acetic anhydride, p-chloroaniline resorcinol plus hydrosulphite, ethylene glycol diacetate, glycerol diacetate, resorcinol monoacetate, resorcinol diacetate, phenyl acetate, furfuryl acetate, ethylidine diacetate, n-propyl furoate, ethyl glycollate, methyl citrate, ethyl tartrate, ethyl malonate, methyl maleate, dimethyl phthalate, benzyl formate, monobutyrin, ethyl carbonate, methyl lactate, diethyl oxalate, methyl adipate, hydroxyhydroquinone triacetate, methyl chlorocarbonate, propylene glycol monoacetate, hydroquinone diacetate, catechol monoacetate, guaiacyl acetate, methyl glutarate, ethyl oxalate, benzyl acetate, diethyl glutacoate, ethyl lactate, diethyl phthalate, ethyl anisate, methyl salicylate, methyl cinnamate, methyl mandelate, methyl acrylate, ethyl oxamate, methyl succinate, ethyl propiolate, ethyl malate, methoxy-benzaldehyde, guaiacol, anisidin, nitroaniso-l, dichloroethyl ether, methoxy acetic acid, methoxybenzyl alcohol, liquid sulfur dioxide, nitromethane, etc., or mixtures of such refining agents which are chemically non-reactive, etc.

The solvent in which I may dissolve the modified rosin or modified rosin ester before contacting it with a selective solvent may be any solvent for the modified rosin or modified rosin ester which is immiscible and non-reactive with the selective solvent used. Thus, I may use a petroleum hydrocarbon solvent such as, for example, gasoline, petroleum ether, a normally gaseous petroleum hydrocarbon held in liquid phase by elevated pressure, low temperature, or both. The concentration of the modified rosin or modified rosin ester in such a solution may be within the range of about 5% to about 80% by weight, and desirably within the range of about 15% to about by weight.

The temperature at which the process in ac-- cordance with my invention may be carried out is dependent upon the selective solvent employed and will be within the range of about 40 C. to about +60 C. In any case, the temperature used will be such that the selective solvent is a liquid under the pressure used.

In the embodiment of my process in which a chemically modified rosin or a chemically modified rosin ester is dissolved in a solvent therefor before it is contacted with a selective solvent, the solution so formed may have a concentration within the range of about 5% to about 40%, by weight. Usually I prefer to use a solution having a concentration within the range of about 10 to about 25% by weight.

The number of washes employed in my process may be varied in accordance with the results desired, and it will be appreciated that the greater the number of washes given the sharper will be the separation of the components of the chemically modified rosin or chemically modified rosin ester treated.

As illustrations of the practical adaptation of the method in accordance with this invention, I may cite the following:

EXAMPLE I Wood rosin polymerized by treatment in solution in ethylene dichloride solution with aluminum chloride, washed with hydrochloric acid and then with water, and recovered by evaporation of the solvent was treated. One hundred grams of this polymerized rosin was dissolved in 300 grams of gasoline. This solution was washed with 75 cc. of furfural, with 25 parts by volume be non-crystalline.

of furfural and then with two portions of 10 cc. of furfural. combined and evaporated to recover the component of the polymerized rosin dissolved therein. Likewise, the gasoline solution was evaporated to recover the component remaining therein.

The two components thus separated from the original polymerized rosin and a sample of the original polymerized rosin were tested by making them into core oils and observing the time required for the core oil to crystallize; The core oil made from the original polymerizedrosin had crystallized in about 105, days, showing it to The component of the polymerized rosin recovered from the gasoline solution after treatmentwith furfural crystallized from core oil in five days showing it to be unpolymerized rosin. On the other hand, the component of the original polymerized rosin recovered from the furfural had not crystallized from core oil in one hundred and forty days, compared with about one hundred and five days for the original polymerized rosin, showing it to be more highly polymerized than the original rosin. These core oil tests demonstrate that the process in accordance with this invention separated the rosin polymerized by treatment with aluminum chloride, into two components one of which is a highly polymerized andthe other an ordinary unpolymerized rosin.

EXAMPLE II A stock solution was prepared which contained 25% of rosin. The rosin present in this solution was composed of 50% I-wood rosin and 50% I wood rosin hydrogenated to the extent of 50% of the theoretical for two double bonds. Three portions of this stock solution of 200 cc. each were counter-currently washed with three portions of 200 cc. of furfural at room temperature, so that the spent furiural from the first stage successively passed on to stage 2 and finally stage 3. The three furfural washed gasoline solutions, and the three furfural solutions, were evaporated to recover the rosin components dissolved therein. The various components thus secured were analyzed with the results given inTable 1 which follows:

Table 1 Refractive Hydroindex genation Gmde Yleld Percent Percent Original blended rosin. 1. 5361 32 H Rosin from gasoline sol.

No. l 1.5264 65 N-l- 18. 7 Rosin from asoline sol. 1. 5312 47. 5 N+ 67.

sol e sol o. 1. 5335 40. 0 N 95.0 Fraction from combined furfural wash solutions. 1. 5422 0. 0 37. 0

An inspection of the above example shows that the original blended rosin having a 32% hydrogenation was separated into fractions which ranged from 0.0% hydrogenation to 65.5% hydrogenation. I

EXAMPLE III A hydrogenated I wood rosin saturated to the extent of 60% was used in this experiment. Three portions of 300 grams each were countercurrently washed with five portions of 100 cc. each of furfural. The resulting gasoline solutions and the combined furfural solutions were evaporated under reduced pressure. The prod- The furfural wash solutions were i ucts thus secured showed the following results on analyses: I

. Table 2 Refractive Hydroindex genation ,Ymld

. v Percent Percent Original hydrogenated rosin 1 l. 5255 60 Fraction from gasoline so]. No. 1.- 1. 5218 78 44. Fraction from gasoline sol. No. 2 1. 5230 74 v 66. 2 Fraction from gasoline sol. No. 3... 1. 5243 y 68 81.1

Fraction from combined furiural fractions l. 538 22 An'inspection of the above table shows that the furiural wash removed unhydrogenated or slightly hydrogenated rosin from the hydrogenated rosin contained in the gasoline solution, so that the saturation of the hydrogenated rosin recovered from the gasoline solution was in-.

creased to as high as 78%. Asa comparison it will be noted that the rosin recovered from the furfural was saturated to the extent only of 22%.

EXAMPLE IV Drop i I Refractive Specific g gf index rotation Yield O. Percent Original Hyex rosin 83 1. 5426 Fraction from gasoline 50]. No. 1 72': 1. 5375 +52. 3 17. 5 Fraction from gasoline i $01. No. 2 78 1. 5376 +53. 4 22- 5 Fraction [rom gasoline $01. No. 3 80. 5 1. 5400 +55. 4 '31. 5 Fraction from aqueous phen 86. 0 1. 539 +61. 4 21. 6

An examination of the'above table shows that the treatment separated the original Hyex'rosin into two components having quite. difierent physical characteristics from one another. A comparison of the properties of the component from gasoline solution 3 and those of the component from the aqueous phenol brings this out.

Thus, the aqueous phenol component had a definitely higher melting point, a lower refractive index and a higher specific rotation than the fraction from the gasoline solution.

EXAMPLE V A gasoline solution containing Hyex rosin was prepared. Three portions, 300 parts by vol-' ume ofeach, of the solution were counter-currently washed with one portion offurfural of fifty parts by volume and four portions of furfural of thirty parts by volume, so that each of the gasoline solutions received four countercurrent washes. The gasoline solutions'and the combined furfural wash solutions were evaporated under reduced pressure, and the properties of the rosin components recovered determined by analysis. Their characteristics are given in Table IV which follows:

Table 4 Drop Refracv melting if? tive S33E23 Yield point index Fraction from gas- C'. Percent oline sol. N0. 1.. 75. 5 156. 5 l. 5371 +50. 21. Fraction from gasoline $01. No. 2 77. 5 160. 5 l. 5378 +54. 5 25. 6 Fraction from gasoline sol. N0. 3.- 82.0 163. O 1. 5382 +53. 4 32. 8 Fraction from furfural s01ution.... 90.0 161.5 1.5527 +60.2 15.2

i In the above Table 4, as in Table 3 of Example IV, the characteristics of the separated components show them to be difierent types of rosin.

EXAMPLE VI Three portions of a solution of hydrogenated I grade wood rosin in gasoline of 200 grams each were counter-currently washed with methyl thiocyanate at (3., so that each gasoline solution received five washes with 20 cc. of methyl thiocyanate. The three refined gasoline solutions and the combined thiocyanate solutions were evaporated under reduced pressure to recover the rosin fractions dissolved in each. The analyses and yields of these fractions of the hydrogenated rosin, as well as that of the original hydrogenated rosin, are given in Table 5 which follows:

An inspection of the data of Table 5 shows that the treatment with the methyl thiocyanate solution separated the hydrogenated rosin having a saturation of 62.5% of theoretical into fractions having saturations within the range of 67-72% of theoretical on one hand and of theoretical on the other. Thus, the thiocyanate tended to selectively dissolve unhydrogenated rosin from the more highly hydrogenated rosin which remained in the gasoline solution.

EXAMPLE VII Three portions of a 20% solution of dihydroabietyl alcohol in gasoline of 50 grams each were counter-currently washed with methyl thiocyanate at 0 C., so that each gasoline solution received five washes with 10 cc. portions of methyl thiocyanate. solutions and the combined thiocyanate solutions were evaporated under reduced pressure torecover the dissolved fractions. The analyses and yields of these fractions of the dihydroabietyl alcohol are given in Table 6.

The three refined gasoline.

An inspection of the data of Table 6 shows that the original sample of dihydroabietyl alcohol was 81% alcohol, while the fraction recovered from the combined methyl thiocyanate solution was 91.5% dihydroabietyl alcohol. As compared with this the fraction recovered in the No. 1 gasoline solution was only 75% dihydroabietyl alcohol. Thus, the treatment in accordance with this invention definitely concentrated the alcoholic portion of the original dihydroabietyl alcohol in the methyl thiocyanate fraction,

EXAMPLE VIII Three portions of 100 grams each of a 20% solution of dihydroabietyl alcohol in gasoline were washed counter-currently with aniline at 0 0., so that each gasoline solution received five washes with 10 cc. portions of aniline. The three refined gasoline solutions and also the combined aniline solutions were evaporated under reduced pressure to recover the dissolved products. The analyses and yields of these products are given in Table 7 which follows:

Table 7 D. n. A. Hydroxyl Alcohol g gfi recovered Percent Percent Grams Original dihydroabietyl alcohol- 4. 75 81 Dihydroabietyl alcohol from gas.

sol. No. 1 4. 4 75 9. 5 Dihydroabietyl alcohol from gas.

sol. No. 4. 65 78. 5 16. 5 Dihydroabietyl alcohol from gas.

sol. N0. 3 4. 7 80 19. 2 Dihydroabietyl alcohol f In combined aniline solutions 4. 75 82 11. 3

An examination of the above data shows that aniline, like the methyl thiocyanate of the Example VlI selectively dissolves the dihydroabietyl alcohol, yielding a fraction which was materially purer than the original sample.

EXAMPLE IX A glycerol ester of hydrogenated wood rosin (hydroabietic acid) was dissolved in gasoline to a 20% concentration. Three portions of 200 cc. each of this 20% solution were counter-currently washed at 25 C. so that each portion received six washes with 20 cc. portions of 85% phenol. The three refined gasoline solutions and the combined phenol solutions were evaporated under reduced pressure. The analyses and yields of the fractions thus'recovered are given in Table 8.

' Original methyl hydro-abietate.

Table 8 Refractive index at I Yield 20 C.

- i v Grams Original glycerol ester 1.5303 Ester from gas. sol. No. l 1. 5303 25 Ester from gas. sol. No. 1 5305 35 Ester from gas. sol. No. 1. 5314 37 Ester from combined phen 1. 5316 Since it is known that the less saturated products have higher refraction indices, a compari-- son of the refractive index of the original ester with that of the fraction secured from the combined phenol extract shows that the latter contains less saturated materialthan the original, and isia definitely different material.

EXAMPLE X The methyl ester of hydrogenated wood rosin ester are given in Table 9.

Table 9 Satura- Refractive index Yielg Percent Grams 1 5177 40 Ester from gas. sol. No. 1.... 1. 5148 28 Ester from gas. sol. No. 2 l. 5163 43 31 Ester from gas. sol. No. 1. 5164 43 38 Ester from combined furfural ext... 1 528 22 An examination of the data given in Table 9 shows that the hydrogenated abietyl ester was concentrated in the gasoline solution #1 while the unhydrogenated ester was concentrated in the furfural extract. v

EXAMPLE 2E The glycerol ester of Hyex wood rosin was dissolved in gasoline to produce a 20% solution;

Three portions of 200 grams each of this solution were counter-currently washed with furfural at room temperature (25 C.) so that each portion;

.received washes with six 20 cc. portions of furfural. The gasoline solutions and the combined furfural' washes were then evaporated under redu'ced pressure. The analyses and yields of the recovered products are given in Table/10.

' A comparison of the refractive indices of the original ester, the fraction recovered from the #1 gasoline solution and the fraction recovered y from the furfural solution, shows that the original ester of Hyex rosin has been separated into two chemically different fractions by the fur fural wash.

EXAMPLE XII- The glycerol ester of polymerized wood rosin at room temperature (25 C.).

' gasoline solutions and the combined furfural solutions were evaporatedunder reduced pressure layer.

was dissolved in gasoline to produce a 25 solution. Three portions of 200 grams eachof this solution were counterecurrentlywashed with one '75 cc. portionand five 55 cc. portions of furfural The resulting to receover the components dissolved in each solution. I The results obtained are given in Table 11. 1

. Table'll Refractive Drop I index melting I Grade Yield 20 0. point Original glycerol ester of C. Percent polymerized rosin 1. 5504 117. 0 D l Ester from gas. sol. No. 1. 1. 544 124. 5 E 14. 2 Ester from gas. sol. No. 2. 1. 544 118.5 E 17. 9 Ester from gas. sol. N o. 3. l. 543 118.0 E 18 9 Ester from combined iur-' I .iura1washes 1.551 110.0 D 49.0

The differences in the refractive indices, melt i gmointand grade demonstrate the separationv of the original glycerol ester of polymerized rosin intocomponentsof different composition, properties and color.

EXAMPLE XIII Three portions of 200, grams each of the 'same gasoline solution of the glycerol ester of polymerized rosin described in Example XII were counter-currently washed with one '75 cc. portion and five 55 cc. portions of aqueous phenol at room temperature (25 (2.). The resulting gasoline solutions and the combined phenol solutions were evaporated under reduced pressure to recover the components dissolved in each. The

results obtained are given in Table 12.

Table 12 Drop Refractive melting Grade Yield 7 1ndex200. point Original glycerol ester of C'.. Percent polymerized rosin 1. 5604 117.0 D Ester from gasoline sol. .1

so I o. 1 1.5466 80.0 F 4.4 Ester from gasoline sol.

No. 1. 5471 81.0 F -4. 7 Ester from combined I phenol washes I 1.549 121.0 D 87.9

f '-A comparison of therefractive indic es, melting-points and grades show that the original ester has'been separated intochemically different fractions by the. phenol wash.

' EXAMPLE XIV The methyl ester of, polymerized wood'rosin was dissolved in gasoline to produce a 25% solution. Three portions of 1.40 grams each of this solution were counter-currently washed with one cc. portion and three 39 cc. portions of methyl thiocyanate. After each wash the solutions were cooled in a bath ofice water to provide more complete separation of the methyl thiocyanate The resulting gasoline solutions and the combined methyl thiocyanate. washes were then evaporated under reduced pressure to recover the componentsdissolved in each solution. The results obtained are given in Table 13. I

Table 13 Refractive Specific index20C. rotation Grade Yleld Original methyl ester of Degrees Percent polymerized rosin 1. 1.5408 +18. 8 D Ester from gasoline sol.

No. 1 1. 5325 +6. 9 H+ 1.9 Ester from gasoline sol.

No. 2 1.5348 +14. 3 H 8.0 Ester from gasoline sol.

No. 3 1.5349 +16. 9 G 10.3 Ester from combined methyl thiocyanate washes 1. 5427 +19. 5 D 79. 8

The differences in the refractive indices, specific rotation and grade show the separation of the original ester into components of different composition, properties and color.

It will be understood that the above examples and details of operation are given by way of illustration only, and that the scope of my invention as herein broadly described and claimed is in no way limited thereby.

This application forms a continuationin-part of my application, Serial No. 160,725, filed August 24, 1937, entitled Method for the separation of chemically modified rosins and their esters into components.

What I claim and desire to protect by Letters Patent is:

1. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized rosin ester in a solvent therefor, contacting the solution so formed with a selective rosin color-body solvent immiscible with the said solution, separating the I selective solvent therefrom and recovering a component of the polymerized rosin ester from each of the resulting solutions.

2. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized rosin ester in a solvent therefor, contacting the solution so formed with a selective rosin color-body solvent immiscible with the said solution, separating the selective solvent therefrom and recovering a component of the polymerized rosin ester from each of the resulting solutions, by evaporating the solvent.

3. The method of separating an ester 01 polymerized rosin into its components, which comprises dissolving the polymerized rosin esterv in a solvent therefor, contacting the solution so formed with furfural, separating the selective solvent therefrom and recovering a component of the polymerized rosin ester from each of the resulting solutions by evaporating the solvent.

4. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized rosin ester in a solvent therefor, contacting the solution so formed with phenol, separating the selective solvent therefrom and recovering a component of the polymerizedrosin ester from each of the resulting solutions by evaporating the solvent.

5. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized rosin ester in a solvent therefor, contacting the solution so formed with an alkyl thiocyanate, separating the selective solvent therefrom and recovering a component of the polymerized rosin from each of the resulting solutions by evaporating the solvent.

6. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized jrosin ester in a petroleum hydrocarbon solvent, contacting the solution so formed with a selective rosin color-body solvent immiscible with the said solution, separating the selective solvent therefrom and recovering a component of the polymerized rosin ester from each of the resulting solutions by evaporating the solvent.

'7. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized rosin ester in a petroleum hydrocarbon solvent, contacting the solution so formed with furfurahseparating the furfural thereiromand recovering a component of the polymerized rosin ester from each of the resulting solutions by evaporating the solvent.

8. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized rosin ester in a petroleum hydrocarbon solvent, contacting the solution so formed with phenol, separating the phenol therefrom and recovering a componentv of the polymerized rosin ester from each of the resulting solutions by evaporating the solvent.

9. The method of separating an ester of polymerized rosin into its components, which comprises dissolving the polymerized rosin ester in a petroleum hydrocarbon solvent, contacting the solution so formed with an alkyl thiocyanate,

separating the alkyl thiocyanate therefrom and recovering a component of the polymerized rosin ester from each of the resulting solutions by evaporating the solvent.

10. The method of separating a glycerol ester of polymerized rosin into its componentsvlhich comprises dissolving the said ester in a petroleum hydrocarbon solvent, contacting the solution so formed with furfural, separating the furiural therefrom and recovering a component of the polymerized rosin ester from each of the resulting solutions by evaporating the solvent.

JOSEPH N. BORGLIN. 

